Dijkstra's vs BFS
Learn when to use each pattern and make the right choice in your coding interview.
Quick Answer
Use Dijkstra when edges have different weights (weighted graph)
Use Bfs when all edges have same weight (unweighted graph)
Side-by-Side Comparison
Dijkstra
Best For
Weighted shortest path, road networks
Time
O((V+E) log V)
Space
O(V)
Bfs
Best For
Unweighted shortest path, maze solving
Time
O(V+E)
Space
O(V)
How to Decide
- All edges have weight 1? → BFS is simpler
- Different edge weights? → Dijkstra required
- Negative weights? → Neither (use Bellman-Ford)
- Need actual shortest distance? → Check weights first
Practice Both Patterns
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